Updated: Tuesday, September 11th, 2012 at 3:54pm

SANTA FE — Labor unions and a retiring Democratic legislative leader have provided nearly $400,000 to a newly formed political group planning to make independent campaign expenditures in New Mexico, including races that will determine whether Democrats retain control of the Legislature.

The new group could provide Democrats with a counterbalance to a super PAC organized by Republican Gov. Susana Martinez’s supporters earlier this year to target legislative races and improve the first-term governor’s chances of moving her agenda through the Legislature.

Democrats have long controlled the Legislature but the GOP hopes to pick up enough seats in this year’s elections to potentially gain a majority in the House and narrow the Democratic advantage in the Senate.

A finance report filed by the new political action committee — Patriot Majority-New Mexico PAC — shows its top donor was the American Federation of State, County and Municipal Employees, which gave $250,000 late last month. A political committee operated by retiring House Speaker Ben Lujan, a Santa Fe Democrat, contributed $83,816, and $49,500 came from a political action committee connected to the National Education Association, a teachers union, and $10,000 from a New Mexico affiliate of the plumbers and steamfitters union.

As a so-called super PAC, the independent expenditure group is free from New Mexico’s campaign contribution limits. It can raise and spend money in unlimited amounts, but its expenditures cannot be coordinated with candidates. Typically, the PACs run TV advertisements and send out mailings for or against candidates.

The PAC registered with the secretary of state last month, and its president is Washington, D.C.-based Democratic strategist Craig Varoga, who runs a national super PAC called Patriot Majority that’s involved in U.S. Senate and congressional races. In 2008, his group ran TV ads against New Mexico GOP Senate candidate Steve Pearce and Republican Darren White in the 1st Congressional District.

“This year, we anticipate supporting state candidates in non-federal races who share our policy goals of creating jobs, improving schools, protecting the environment and standing up to the special interests who would harm New Mexico and its people,” Varoga said Tuesday in a statement. “We expect to begin our independent communications in the coming weeks.”

The committee raised $393,816 in July and August, and has most of that left after spending only $62 for a bank fee and the costs to register as a political committee in New Mexico.

The super PAC allied with Martinez — Reform New Mexico Now — had cash-on-hand of $305,000 as of last week after raising $281,000 in the past two months.

Jay McCleskey, the governor’s top political adviser, said the PAC will focus on two dozen legislative races and support candidates backing the governor’s agenda, including a new teacher evaluation system and stopping New Mexico from granting driver’s licenses to illegal immigrants.

Lujan said he didn’t know what races Patriot Majority planned to target in New Mexico, but made his contribution to help oppose GOP independent expenditure groups.

“I thought, well, if I can just help in that arena then that’s something that can counter all the negatives that we’re going to get,” said Lujan.